Dominic Ford, Editor
From the Inner Planets feed
Venus will reach half phase in its 2018 evening apparition. It will be shining brightly at mag -4.3.
The table below lists how high Venus will appear at sunset over the course of the apparition. All times are given in Ashburn local time.
|11 Mar 2018||19:11||20:22||14°||west|
|21 Mar 2018||19:21||20:44||16°||west|
|31 Mar 2018||19:31||21:07||18°||west|
|10 Apr 2018||19:40||21:30||21°||west|
|20 Apr 2018||19:50||21:54||23°||west|
|30 Apr 2018||20:00||22:17||25°||west|
|10 May 2018||20:09||22:37||26°||west|
|20 May 2018||20:18||22:54||28°||west|
|30 May 2018||20:26||23:05||28°||west|
|09 Jun 2018||20:33||23:11||29°||west|
|19 Jun 2018||20:37||23:10||28°||west|
|29 Jun 2018||20:38||23:04||27°||west|
|09 Jul 2018||20:36||22:53||26°||west|
|19 Jul 2018||20:31||22:40||25°||west|
|29 Jul 2018||20:23||22:23||23°||west|
|08 Aug 2018||20:12||22:04||21°||west|
|18 Aug 2018||19:59||21:44||19°||south-west|
|28 Aug 2018||19:45||21:21||17°||south-west|
A graph of the phase of Venus is available here.
Venus's orbit lies closer to the Sun than the Earth's, meaning that it always appears close to the Sun and is lost in the Sun's glare much of the time.
It is observable for a few months each time it reaches greatest separation from the Sun – moments referred to as greatest elongation. These apparitions repeat roughly once every 1.6 years.
On these occasions, Venus is so bright and conspicuous that it becomes the third brightest object in the sky after the Sun and Moon. It is often called the morning star or the evening star.
Venus's phase varies depending on its position relative to the Earth. When it passes between the Earth and Sun, for example, the side that is turned towards the Earth is entirely unilluminated, like a new moon.
Conversely, when it lies opposite to the Earth in its orbit, passing almost behind the Sun, it appears fully illuminated, like a full moon. However, at this time it is also at its most distant from the Earth, so it is actually fainter than at other times.
Venus shows an intermediate half phase – called dichotomy – at roughly the same moment that it appears furthest from the Sun, at greatest elongation. The exact times of the two events may differ by a few hours, only because Venus's orbit is not quite perfectly aligned with the ecliptic.
The coordinates of Venus when it reaches dichotomy will be:
|Object||Right Ascension||Declination||Constellation||Angular Size|
The coordinates above are given in J2000.0.
|The sky on 15 August 2018|
4 days old
All times shown in EDT.
The circumstances of this event were computed using the DE405 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).
This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.
|09 Jun 2018||– Venus reaches highest point in evening sky|
|17 Aug 2018||– Venus at greatest elongation east|
|14 Dec 2018||– Venus reaches highest point in morning sky|
|06 Jan 2019||– Venus at greatest elongation west|
© NASA/Ricardo Nunes